Storage Controller Virtual Stream Lifetime Mapping
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Solution Overview
Problem
Storage devices face limitations in mapping virtual streams onto physical streams due to hardware restrictions, leading to inefficient data storage and garbage collection, particularly when handling a large number of virtual stream IDs exceeding the supported physical stream IDs.
Innovation Solution
A storage device with a controller that receives write and discard commands, determines the lifetime of virtual stream data, and maps virtual streams onto physical streams based on this lifetime, clustering data accordingly to optimize storage and garbage collection operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the storage device supports a limited number of physical stream IDs due to hardware restrictions, then the device complexity is reduced, but the adaptability to hosts assigning numerous virtual stream IDs deteriorates
Solution Approach 1:
The patent introduces a mapping mechanism that acts as an intermediary between virtual stream IDs from the host and physical stream IDs supported by the storage device hardware. The controller maintains a mapping table that translates multiple virtual stream IDs to a limited number of physical stream IDs, enabling compatibility with hosts that assign numerous virtual stream IDs while working within hardware restrictions on physical stream ID capacity
Solution Approach 2:
The patent adds a virtualization dimension by introducing virtual stream IDs as an abstract layer above the physical stream IDs. This dimensional transformation allows the system to handle a larger namespace of stream IDs than the hardware physically supports, effectively resolving the contradiction between hardware limitations and host compatibility requirements
2Device complexity
If virtual streams are mapped onto physical streams without considering data lifetime, then the mapping process is simplified, but the efficiency of garbage collection deteriorates
Solution Approach 1:
The patent changes the mapping parameter from simple stream ID correspondence to lifetime-based mapping. The controller determines the lifetime of data associated with each virtual stream ID and maps it to a physical stream ID based on matching lifetime characteristics. This parameter transformation enables more efficient garbage collection by grouping data with similar retention requirements, improving productivity without excessive complexity increase
3Quantity of substance
If data with different lifetimes are stored together in the same physical blocks, then the storage capacity is maximized, but the precision of lifetime-based management deteriorates
Solution Approach 1:
The patent applies local quality by assigning different storage characteristics to different data based on their lifetime requirements. Data with similar lifetimes are mapped to the same physical stream ID and stored together in specific physical blocks, creating localized storage regions with uniform data characteristics. This enables precise lifetime-based management while still achieving high storage capacity utilization through efficient space allocation
Data Source
AI summary
A storage device includes a controller and nonvolatile memories. The controller receives write commands having virtual stream identifiers (IDs), receives discard commands having the virtual stream IDs, and determines a lifetime of write data to which each of the virtual stream IDs is assigned. The nonvolatile memories are accessed by the controller depending on physical stream IDs. The controller maps the virtual stream IDs and the physical stream IDs based on the lifetime of the write data.